OverviewMap more zoomed out

[deleted-user-FIIGSkDYOcdf]

Is there any way to make the overviewmap control more zoomed out so it shows much bigger map than the default view.

Thanks

[deleted-user-FIIGSkDYOcdf]

So it is applicable or not?

[DominiqueBroux]

The min and max ratio scale ratios of the overview map are not publicly exposed.

One workaround is to get the overview source and to modify it.

[GarimaVyas]

The Overview map doesn't have a way to bind to a custom extent, it automatically picks it up from the map control it is bind to. However, as a way around it, you could use a hidden map control, that does extent calculations from your original map control, on extent changed event handler and you can bind your overview map to that.
A little bit tricky but might work.
XAML:

    <Grid x:Name="LayoutRoot">
        <esri:Map x:Name="MyMap" Extent="-13631774.161,4551117.011,-13629848.904,4552046.199" ExtentChanged="MyMap_ExtentChanged">
            <esri:ArcGISTiledMapServiceLayer ID="TopoLayer" 
                    Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer"/>
        </esri:Map>

        <Grid  HorizontalAlignment="Right" VerticalAlignment="Top" Width="300" Height="200" Canvas.ZIndex="100" >
            <Border CornerRadius="0,0,0,10" Background="#BB919191">
                <esri:OverviewMap x:Name="MyOverviewMap"  
                                  Margin="8,0,0,8" 
                                  Map="{Binding ElementName=MyMap_Ov}">
                    <esri:OverviewMap.Layer>
                        <esri:ArcGISTiledMapServiceLayer ID="StreetLayer" 
                            Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer"/>
                    </esri:OverviewMap.Layer>
                </esri:OverviewMap>
            </Border>
        </Grid>
        <esri:Map x:Name="MyMap_Ov">
            <esri:ArcGISTiledMapServiceLayer ID="TopoLayer1" 
                    Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer"/>
        </esri:Map>
    </Grid>

XAML.CS

        private void MyMap_ExtentChanged(object sender, ESRI.ArcGIS.Client.ExtentEventArgs e)
        {
            MyMap_Ov.Visibility = System.Windows.Visibility.Collapsed;           
            MyMap_Ov.Extent =  MyMap.Extent.Expand(4);
        }